The present invention relates to chair height adjustment mechanisms and more particularly to a control actuator for a pneumatic or gas spring adjustment mechanism.
A fairly wide variety of chair or seating vertical height adjustment mechanisms are currently available. A typical office chair, for example, includes a seat, a back portion and a support pedestal. The support pedestal usually incorporates a chair height adjustment mechanism which raises the seat height with respect to floor level. The pedestal or base may include threadably interconnected and relatively positionable elements. In the alternative, a pneumatic or gas spring is provided for height adjustment. The gas spring includes a piston rod connected to a piston which rides within a cylinder. A release pin extends from an outer end of the cylinder or housing through a seal. The release pin serves as an actuator for releasing or locking the piston in a desired set position and for setting the initial or unloaded chair height. An actuator handle or lever located under the seat cushion of the chair is provided to engage the release pin and selectively release or lock the height adjustment mechanism. The lever or control actuator is typically movable in one of an upward, downward, backward or forward direction. An example of a chair height adjustment mechanism incorporating a gas spring may be found in U.S. Pat. No. 3,711,054 entitled CONTINUOUSLY ADJUSTABLE LIFTING DEVICES and issued on Jan. 16, 1973 to Bauer.
Problems have been experienced with user operation of the control actuators. A user unfamiliar with the particular mechanism will not know which direction within which to move the height control lever or control actuator. If the actuator functions to control the release pin when it is pulled in the upward direction, the actuator handle may be broken or bent should the user place their full weight onto the handle and push downwardly.